1. Technical Field
The present invention relates to a technique for updating a circuit implemented in a device.
2. Background Art
In general, content distributed via a network, content recorded to a recording medium, and the like, is encrypted before distribution in order to prevent unauthorized use of the content and to protect a copyright thereof. In a device for playing back the content, decryption processing is performed to decrypt the encrypted content, and an encryption method is frequently implemented in the device by hardware in view of the required processing speed and tamper-resistance.
There is a desire to update encryption methods implemented by hardware to new encryption methods. In recent years, reconfiguring a circuit and updating an encryption method have become possible by using a reconfigurable device such as an FPGA (Field Programmable Gate Array) or a PLA (Programmable Logic Array)(see patent document 1).
Also, patent document 2 discloses a technique for holding, in a device, a database that stores an algorithm file for updating a circuit, acquiring the algorithm file from the database in accordance with an external instruction, and updating the implemented circuit.
Patent document 1: Japanese Patent Application Publication No. H10-320191
Patent document 2: Japanese Patent Application Publication No. H10-55135